Polytunnels

Polytunnel’s should be cleaned at least once a year, maybe more if your Polytunnel is nearer trees as it will probably have algae forming on the outside and debris from the trees falling onto it. There are different ways in which to clean your tunnel. Here are a few helpful tips :-

If you get a bucket of warm water and add a small drop of washing up liquid, you will then be able to use a soft brush to clean the tunnel, for the bits you cannot reach get an old bed sheet and with a person each side of the tunnel gently go along the tunnel. Be careful not to do anything that will scratch the cover as this will reduce the light transparency.

Weather conditions over the winter period can vary from mild to extremely cold. If we are fortunate enough we may get a White Christmas it would be very wise to clear the snow from your Polytunnel or Glasshouse. Snow is very heavy and can cause structural damage if it builds up. You can remove it using a soft brush, a bed sheet or a rope (but if using a rope on a Polytunnel do be careful not to scratch your polythene as this reduces light transmission).

Many of our competitors Polytunnels were damaged by snow last year, luckily very few of our customers had any issues. Crop support bars are particularly helpful in Polytunnels to strengthen and protect against snow damage. A frost protection heater (which we supply a range of) can have the advantage of making snow melt before it can build up, helping to protect your Polydome Greenhouse or Polytunnel against structural damage.

Polytunnels like other greenhouses provides protection for crops over the colder winter months. The biggest threat to plants during this colder period is frost.

Frost causes the water in plant cells to freeze. The result of this is damage to the cell wall which leads to wilted growth causing the plant to become blackened and distorted.

Under sever frost the temperature will drop to a point where only supplementary heating inside the tunnel will protect against the cold.

But before reaching this point, there are some steps that maximise your tunnels ability to protect against the frost.

Make sure your tunnel is located in the sunniest location of the garden. This allows your tunnel to heat up during the day in the low winter sun.

Clean your tunnel cover annually. This will reduced any obstructions to the sunlight passing through the polythene which will also help heat the tunnel.

Finally make sure when purchasing your tunnel than you only use a thermic plastic, which has good thermal properties. This will help reduce heat loss through the cover thus giving better protection to your crops during winter.

Recently our time for blogging has been limited. There was huge interest in our stand at the ploughing championships. It’s only now we are finally getting through these enquiries and therefore getting back to our day to day duties.

I would like to thank everyone that came to visit our stand during the ploughing championships. Over the coming weeks we hope to contact you all. And look forward to talking with you and answering any questions that you may have as a result of seeing our stand.

As always you can find lots of answers to questions already on your mind at www.polydome.ie and please feel free to contact us directly at our office.

For those taking the next step and investing in a greenhouse, it can be sometimes hard to find which option suits best. My advice is to find a greenhouse that compliments your garden while also being practical for its intended use.

Firstly you should avoid generalising about characteristics of Polytunnels vs Glasshouses (e.g. thinking Polytunnels are stronger than Glasshouses or Vice Versa). There are a huge range of Polytunnels from extremely strong to extremely flimsy and the same applies to Glasshouses. One generalisation one can usually make is that something very cheap is probably very flimsy, and usually to have something strong is going to cost more that something weak.

Sometimes customers ask which is better for growing plants – a Polytunnel or a Glasshouse, but if adequate ventilation is provided (and that depends on the features or model you choose) then the growing conditions are much the same.

Ultimately this debate boils down to personal choice, so instead of given my opinion on which I think is best I have listed below some pros and cons of both Polytunnels and Glasshouses. I hope this makes your search that bit easier…..

Polytunnel Pros

If you are looking for something quite large, the difference in cost between a Polytunnel and a Glasshouse is quite substantial. Vegetables particularly take up a lot of space, so a Polytunnel will give you a larger area of protected space to grow for your money than a Glasshouse – all things in terms of strength and ventilation being equal.

There is more flexibility to customize your structure to suit unusual needs. i.e. widening the doors for machinery or coping with sloping ground, a Polytunnel is much more easily modified than a Glasshouse.

Straight sided tunnels provide a very pleasant working area internally as a result of the height. If your 6’ 2” like me, this is an added plus. It also means taller crops are less likely to be touching off the polythene cover.

Polytunnel Cons

Although Polytunnel Covers are UV stabilised to give long life, they do need to be replaced periodically (depending on the grade chosen usually every 4 or 5 years, but some customers getting much longer – it depends on many factors such as how much sunlight the cover get. With larger structures this can be a bit of a headache, it requires the customer to think ahead and test the polythene when coming up to its expected end of life so to anticipate when to recover it rather than having the cover fail in the middle of a period of inclement weather.

Polytunnels can prove slightly harder to construct as it involves holding a large sheet of polythene, so any wind at all makes covering tricky. Tensioning the polythene to the adequate tension is a developed skill. It is very achievable by all but takes patience and planning when covering ones tunnel for the first time

In a glasshouse if you break a pane of glass you can replace that pane. Do the same with Polytunnels cover and you have to try and tape it (not the best or most permanent job). In the worse case situation you might even have to recover the full tunnel if needs be.

Prone to attack by cats and dogs (and birds pecking at insects at the ridge). Not the most common of problems however I have heard of it occurring on more than a few occasions. Therefore worth noting if you have pets around.

Polytunnels are not an item of beauty to most, so generally people want to keep them out of sight in the vegetable plot.

At present there are not as many options for ventilation in Hobby Polytunnels as there are for Glasshouses. Ventilation is usually only supplied by opening doors at both ends whereas a Glasshouse can have roof vents, louvre vents and these can easily be fitted with automatic opening devices which do not need electricity to work.

Glasshouse Pros

Glasshouses are available in very attractive designs that compliment a garden, such as Orangeries, Victorian style Models and Dwarf Wall Greenhouses, with the frames being available in a range of colours. They do not need to be kept out of sight so can be situated nearer your house and this can be an advantage in terms of making use of it.

Glasshouses will need periodic cleaning as do Polytunnels but you don’t need to replace the covers every few years.

Aluminum has a very long lifespan and powder coated models protect the aluminium from oxidising and so retain the good looks of the Greenhouse for longer.

Glasshouses are available with a wider range of ventilation options than Polytunnels and also there is an abundance of shelving and other accessories for them that are not widely available for Polytunnels. For example rainwater collection from a Glasshouse is simple as they nearly all have built in gutters, it is just a question of ordering downpipes and a water barrel for it.

Glasshouse Cons

A flat and level base is required for a Glasshouse, so generally speaking the preparation of the site is a bigger job than a Polytunnel.

The lead time for supplying some Glasshouses can be up to 3 months, so you need to plan ahead (unless it’s a standard model, these are normally in stock by glasshouse suppliers). Most Polytunnels that are produced in Ireland can be manufactured within days of order.

To summarise

Joking apart, many customers get both a Polytunnel and a Glasshouse. The Polytunnel is at home in the vegetable patch out of sight, doing a fantastic job of protecting the vegetables from excess rain and wind, providing excellent growing conditions, the Glasshouse up near the house, a feature in the garden and used for propagation, flowers, bedding plants and perhaps a few tomatoes. So the question does not have to be Polytunnel or Glasshouse, it can be which Polytunnel and which Glasshouse (probably not all at once).

The difference will amaze you. Free from the ravages of the weather you can create ideal growing conditions for all sorts of vegetables and flowers in a Polytunnel or glasshouse, avoiding the frustrations of growing outdoors. No more plants being drowned by torrential rain, frozen and battered by the wind.

In a Polytunnel or glasshouse you will enjoy an extended growing season, being able to plant earlier in the season with less risk of frost (and even earlier again if you use a frost protection heater) and enjoy plant growth longer than is possible outdoors.

If you are new to growing you will be able to enjoy producing healthy organic crops and if new to growing your own vegetables you are in for a surprise as the taste of fresh vegetables picked and eaten the same day is really fantastic.

Lastly, if you have found Murphy’s law to be true that whenever you have a day off to escape to the quiet of the garden and the weather is most likely to be awful, with a Polydome Greenhouse your personal space will be available to you year round to forget about work and enjoy your hobby no matter what way the weather is.